As a communication manner different from unicast or broadcast, multicast makes “one point sending, multi-point receiving” possible effectively, and is helpful to save bandwidth so as to alleviate burdens on the network. Further, with the multicast characteristic, service provider can provide some new value-added services to consumers conveniently, such as online live, network telecast, remote education, remote healthcare, network radio, real-time video conference, etc.
Taking some widely used multicast service, IPTV, as an example, the multicast source, namely the equipment which initially sends the multicast data out, is generally located at the network side, e.g. content distribution network (CDN). IPTV also has corresponding solutions for multicast service management, the user multicast permission management and multicast charging management.
Along with the growth of network bandwidth, end users are not satisfied with being just service receivers, hence, there comes the need of setting multicast source device at the user side. Hereinafter, multicast, the multicast sources of which are located at the side of users, will be referred to as uplink multicast, and the multicast source for the uplink multicast will be referred to as uplink multicast source, accordingly, traditional multicast, the multicast sources of which are located at the network side, will be referred to as downlink multicast.
However, in view of the complexity of uplink multicast service and some economy factors, the operators and service providers prohibit uplink multicast service in traditional access network. Moreover, in traditional multicast protocols and also the related standards for control, there is few solution for the access control, bandwidth control for uplink multicast.
According to the prior art, there are two solutions to support uplink multicast services:
Solution 1: user equipments (UE) send data streams which are expected to be multicasted in the form of unicast data to the network side, the unicast data will be then converted into multicast data after being processed by a dedicated device at the network side, later, the consequent multicast data will be conveyed to a multicast device, without loss of generality taking a multicast router as an example, which will then provide multicast service to other UEs.
Although solution 1 make it possible that a UE can provide service data to other UEs, the UE is still sending unicast data, more than this, people find no favor with solution 1 for the following reasons: a conversion device is required for the conversion from unicast to multicast, which raises the cost for the operators and service providers; the conversion is quite resource (e.g. the processing capability of the hardware) consuming.
Solution 2: an end to end transparent service channel, sourced from the UE to the multicast router at the network side, is established for each UE which needs to send multicast service. All uplink data including multicast data and unitcast data from that UE will be forwarded to a dedicated cross connected VLAN (CC-VLAN) which is like a special line in special line communication, by doing so, the multicast data stream will reach the network side and be provided to other UEs by the multicast router(s).
Solution 2 is not perfect either. First, both unicast data and multicast data will get directly to the network side where the multicast server is located, the uplink data can not be filtered or controlled necessarily in access network by the operators and service providers; second, it costs a large number of VLAN resources to establish a dedicated CC-VLAN for every UE having the need of sending multicast data, and hence does not fit for commercial application; third, whilst applying solution 2 to a UE, the UE can not request multicast service provided by other UEs on demand or carry out its normal unicast service.
In view of the above, an optimized solution for controlling the transmission of uplink multicast service data is needed, preferably, the solution should neither occupy very much network resources nor impact other normal services of the UE.